Stencil sheet



Patented Apr. 8, 1 930 Io Drawing.

srmnmo norm, or 'rox'vo, JAPAN STENCIL snEEr This invention relatestoimprovements in stencil sheets for use in duphcating manu-- script andtypewritten documents, drawings and the .like.

Heretofore, such stencil sheets are generally made of thin tissue paper,such as Japanese paper,jcoated or im regnated with some substancesimpermeab e to ink, which coating can be removed by the pressure of ahand stylus or the impactof the type of the writing machine.

The Japanese papers commonly used as the base material are made from thebasts of the plants indi enous to J apan-viz the paper mulberryroussonetia-papyrifem) Mitsumata (Edgwortb/ia-papyrifem) and Gampi(Wickstroema-cane'scens) The Japanese have made their characteristicpapers from the earliest times by the most primitive means from thebasts of these plants. The isolated tissue, consisting of a closenetwork of fibers,

is simply cut and-hammered to produce a surface of the requisiteevenness; and the complete production of a web of paper.

The stencil sheet according to the present invention, comprises a baseof thin Japan paper, consisting of highly hydrated long fibers andhaving the maximum felting and grease-proofing qualities, coated with a.suitable coating composition which renders it ink-resistant.

In practice, the base material is prepared by the bast tissue of thepaper mulberry, Mitsumata or Gampi being subjected to a definite wetnessby a lengthy hydration process of the beating soas 'to produce a paperof the maximum felting and greaseproofing' qualities, whereupon thepaper is coated with a suitable coating composition including waxes or agelatinous organic colloid, such as gelatine, or cellulose esters,combined with a suitable tempering agent.

In the beating process, the degree of hydration, or beating units whichproduce the maximum felting and grease-proofing qualities are 40 to 60by the well-known Schoper-Riegler beating tester.-

For pur oses of illustration, the follow-:

in examp es are given:

sample 1.The isolated bast tissue of 2.

Application flle'd August 4, 1927, Serial No. 210,728.

mulberry (J apanesez K 020) is beaten with a wooden hammer for aboutfive hours, the wetness being carefully controlled so as to reach thedefinite point with the aid of the Schoper Riegler beating tester. Thedegree of hydra-- tion, or beating units which produce the maximumfelting and zgrease proofing qualities are 40 to 45.

' Example 2. The isolated bast tissue of Mitsumata or Gampi is subjectedto free beating for about 20 minutes in a beating engine which isfollowed by wet beating for about five hours, the wetness beingcontrolled so as to reach the units of to by the Schoper-Riegler tester,which enables a paper of the maximum felting and grease-proofingqualities to be produced.

The degree of hydration may, of course, be varied within the scope ofthe invention, and there is also permissible a certain variation in thebeating units described.

Inthe heating process, the cutting of the fibers must be avoided. It isadvantageous to blend the difierent kinds of beaten stuffs in anysuitable proportions to produce therequired strength and toughness ofpaper. The paper is made in the usual Japanese manner, Neri, a colloidalmucilage of some plants being added to the stufi's.

The Japanese paper commonly used as the base material is an absorbentpaper which is poor in felting and grease-proofing qualities. Thecoating composition being readily absorbed thereby, it is impossible toform a thick layer of coating on the surface of paper. Practically, itis found to be 01 prime importance that in order to give a clear writingsure 0 the types of a typewriting machine.

Moreover, the stencil sheet has considerable strength and durability andgives a large number of copies.

I claim:

1. A stencil sheet for stencilization by pressure, comprising a base ofthin Japanese paper of the maximum felting and grease- 5 proofingqualities, consisting of highly hydrated bast fibres, and coated with acoating material impermeable to ink.

2. A stencil sheet for stencilization by-pressure, comprising a base ofthin Japanese paper consisting of the bast tissue of a definite wetnessso as to produce the maximum felting and grease-proofing qualities, andcoated with a coating material impermeable to ink.

In testimony whereof I a'ffix my signature.

SHINJIRO HORII.

